"Chance for Rare Monsters to Fracture on death" makes Breach monsters invisible & undamageable

Bug Report ID: #2,652,922,599

I just did a map as a part of one of Eagon's memory chains that had the affix "29% chance for Rare Monsters to Fracture on death" and this appears to be bugged for rare Breach monsters. When this triggered for a Breach rare, I would start getting attacked by an unknown number of invisible magic Breach monsters--their attacks were visible and dealt damage and I could mouse over where they were because their name/life bar would appear, but they themselves were undamageable.

This was mostly innocuous at first, but the Breach that spawned in the map was a hive, so it became more and more problematic as more and more waves spawned and rares died. I wondered if they could target Ailith, and about as soon as I had that thought, they answered that question for me by bursting her down and causing me to fail the encounter.

I've experienced it too, not just from breach monster but i think it's from originator pack as well, the invisible monster keeps shooting a projectile.